1. Technical Field
The disclosure relates to an inductor, and more particularly, to a device of inductance detection and the method using the same.
2. Related Art
Recently, portable electronic products have developed and used in a wide range of fields, and have encountered a power management issue. Due to the electric power limitations of portable electronics products, power management IC has become a key component for effectively managing electric power consumption. Power management IC transforms a voltage of the battery to the different operation voltages of the sub-circuits of the portable electronics product, such as transforming 3.3V to 1.2V, or 3.3V to 2.5V, etc. The design guide of the voltage transforming for the power management IC is high efficiency, high precision, low noise, and small volume. Generally speaking, there are three kinds of voltage transformer inside the power management IC: switching regulator, linear regulator, and charge pump regulator.
The switching regulator is a high efficient voltage transformer, and theoretically, it could have 100% transforming efficiency. Nowadays, the outside voltage supplied usually is a single voltage level; conversely, the electric system uses a multi-voltage providing system for different voltage level requirement, through a embedded multi-voltage switching regulator, to provide multi-level voltages to the system. Otherwise, a high efficient switching regulator is a popular choice since it reduces power consumption.
Please refer to FIG. 1, which depicts the inside architecture of a conventional switching regulator, adopting a PWM (Pulse Width Modulation) control signal to control a transistor to transmit an output voltage (Vout) with a high frequency noise to an outside inductor and capacitor. After a low pass filter composed by the outside inductor and capacitor filters the high frequency noise, a stable fixed voltage without noise is outputted to the load. Usually, the switching regulator uses the outside inductor and capacitor for filtering when the power is transformed.
There are several problems for conventional switching regulator when using the outside inductor and capacitor:                1. The passive components are made smaller than ever, causing a problem of the similarity of each component. When bonding the tiny inductor on the output end of the switching regulator, if a resistor was wrongly chosen and bonded, the switching regulator may malfunction due to misuse.        2. If the impedance of the outside inductor is inappropriate, the switching regulator would be damaged due to the over voltage. The conventional switching regulator design does not provide an appropriate protection mechanism for this situation.        
There is therefore a need to provide an active checking mechanism for the correctness of the outside component of the switching regulator, to prevent potential damage caused by misusing the outside component.